An ultrastructural study of pyrenoids inLeptosiropsis torulosa

Summary The ultrastructure of the mature pyrenoid of the chaetophoracean algaLeptosiropsis torulosa is unlike any described for the green algae. The nucleus is surrounded by the pyrenoid, with only the endoplasmic reticulum interrupting the encircling pyrenoid. The pyrenoid possesses only the appressed plastid membranes that are in contact with the nucleus, with no traversing thylakoids present.     

High-Resolution,Non-Invasive Imaging of Upper Vocal Tract Articulators Compatible with Human Brain Recordings

A complete neurobiological understanding of speech motor control requires determination of the relationship between simultaneously recorded neural activity and the kinematics of the lips, jaw, tongue, and larynx. Many speech articulators are internal to the vocal tract, and therefore simultaneously tracking the kinematics of all articulators is nontrivial—especially in the context of human electrophysiology recordings. Here, we describe a noninvasive, multi-modal imaging system to monitor vocal tract kinematics, demonstrate this system in six speakers during production of nine American English vowels, and provide new analysis of such data. Classification and regression analysis revealed considerable variability in the articulator-to-acoustic relationship across speakers. Non-negative matrix factorization extracted basis sets capturing vocal tract shapes allowing for higher vowel classification accuracy than traditional methods. Statistical speech synthesis generated speech from vocal tract measurements, and we demonstrate perceptual identification. We demonstrate the capacity to predict lip kinematics from ventral sensorimotor cortical activity. These results demonstrate a multi-modal system to non-invasively monitor articulator kinematics during speech production, describe novel analytic methods for relating kinematic data to speech acoustics, and provide the first decoding of speech kinematics from electrocorticography. These advances will be critical for understanding the cortical basis of speech production and the creation of vocal prosthetics.     

Nonenzymatic incorporation of glucose and galactose into brain cytoskeletal proteins in vitro.

Initial studies demonstrated the loss of lysine and simultaneous appearance of glucitollysine in intracellular proteins following incubation with sugar. For example, when a crude nervous tissue cytoskeletal preparation was incubated in 100 mM glucose for 10 days, > 60% of the lysine residues were modified. Over 20% of the lysyl residues in a spinal cord neurofilament preparation are susceptible to Schiff base formation after one day and over 30% following five days of incubation with 100 mM glucose. When incubated with 100 mM galactose, F- and G-actin were found to be significantly modified in as few as 15 h, with > 70% of the lysyl residues lost. After 45 h of incubation, > 90% of the residues had been modified. These data also indicate that many of the lysyl residues in F- and G-actin are exposed and very susceptible to modification by sugar. This rapid and extensive modification of lysine in actin in vitro suggest that it may be modified in diabetic nervous tissue.     

STRUCTURE OF THE ANISOGAMETES OF THE GREEN SIPHON PSEUDOBRYOPSIS SP. (CHLOROPHYTA)1

The fine structure of the male and female gametes of Pseudobryopsis, particularly that of the flagellar apparatus, is compared with that of swarmers of other green algae. There is general similarity, with differences in detail, to the Ulvales and other green siphons that have been studied. The similarities include overlapping basal bodies, the capping plate type of connective between basal bodies, terminal caps, and system II fibrous roots (rhizoplasts). The capping plate of the female gamete differs from that in other green siphons and the Ulvales in form and in the presence of a faint striation. A diagram illustrating the actual arrangement of the components of the flagellar apparatus is given, along with a discussion of the fact that the mirror image of the true arrangement has been given in some reports on ulvaphycean algae.     

Interaction of multiple factors with a GC-rich rlement within the mitogen responsive region of the human transferrin receptor gene

Nuclear factors from HeLa cells were isolated by elution of DNA-cellulose bound proteins with a double stranded synthetic oligonucleotide corresponding to the region from ?34 to ?79 of the human transferrin receptor (TR) gene promoter. The eluted proteins were further purified and separated from the oligonucleotide by ion exchange chromatography. Proteins within the resulting fraction bound with specificity to the TR promoter. Retardation gel analysis and competition with specific double-stranded oligonucleotides show that multiple factors present in this fraction compete for binding within the same region of the TR promoter. Footprinting experiments demonstrate that these factors contact a GC-rich element that is within the region that is required for enhanced expression of the gene in proliferating cells. One of the factors protects an extended DNA sequence but, still contacts the GC-rich element.